1. Field of the Invention
The present invention relates to a behind the ear hearing aid system, and more particularly, the invention relates to a hearing aid system having an open ear canal hearing aid eartip.
2. State of the Related Art
Present day hearing aids have been developed to correct the hearing of users having various degrees of hearing impairments. Generally, hearing loss is not uniform over the entire audio frequency range. For example, hearing loss for sounds at high audio frequencies (above approximately 1,000 Hz) will be more pronounced for some people with certain common hearing impairments, while hearing loss for sounds at lower frequencies (below approximately 1,000 Hz) will be more pronounced for people having different hearing impairments.
The largest population of people having hearing impairments include those having mild hearing losses with normal or nearly normal hearing in the low frequency ranges and hearing losses in the higher frequency ranges. The most problematic sounds for people having such mild hearing losses are high frequency sounds at low amplitudes (soft, high-pitched sounds).
The traditional approach for correcting hearing impairments has been to employ either an electronic “in the ear” (ITE) hearing aid device inserted into the ear of the user or a “behind the ear” (BTE) hearing aid device attached behind the ear. The ITE hearing aid devices are custom made to fit within the ear and ear canal of the particular user. The BTE hearing aid devices include a flexible plastic tube connecting a behind the ear device to an ear mold placed within the ear. Both the ITE and BTE hearing aid devices tend to block the ear canal so that little or no sound can reach the ear in a natural, unaided manner.
Hearing aid systems which block the ear canal almost entirely cause a problem known as the occlusion effect. The occlusion effect is caused by the increased transmission of sound by bone conduction when the ear canal is blocked and ear conduction is impeded. This occlusion effect results in sounds which are unnatural and uncomfortable for the user. In particular, the user's voice sounds unnaturally higher than normal.
Some hearing aid systems have been made employing vents in the ear mold which reduce the occlusion effect partially. These vents allow the user to hear some natural sounds through a device positioned in the ear. Although vents provide some improvement in decreasing the occlusion effect, distortion of the user's voice remains a problem.
In an effort to alleviate some of the aforementioned problems, some BTE hearing aids have been designed with a flexible tube that extends into the ear canal and is held in place within the ear canal by an ear mold that leaves the ear canal generally unobstructed. Although the relatively open ear canal of these devices overcomes some of the occlusion effect, these hearing aids suffer from a number of other significant problems. For example, the BTE hearing aids employ a rigid plastic ear hook to secure the BTE device on the ear. The ear hook connects a hearing aid casing positioned behind the ear to a flexible plastic tubing which extends into the ear. The relatively large and rigid ear hook and the connection between the ear hook and the flexible tubing are visible and aesthetically unpleasing. The large size and visibility of the BTE hearing aid components results in a cosmetically unattractive device.
A flexible tube is used which can be cut to an appropriate length for a particular user. The ear mold which secures the end of the flexible hearing aid tube within the ear canal has to be custom manufactured to fit the user's ear to sufficiently secure the hearing aid tube in place in the ear canal and prevent the ear mold from falling out of the ear, for example, when the user is jogging. The custom made ear mold adds to the cost of the device and the time needed to fit the hearing aid.
There are some stock ear canal eartips available which are generally used during a trial period when the hearing aid is being tested or while the ear mold is being made. Some of these stock ear canal eartips are formed of hard materials, some are formed of solid rubber, and some are formed of foam. In general, stock ear canal eartips which are currently available have problems with holding the end of the flexible hearing aid tube securely in place. When these stock ear canal eartips fit tight enough to hold the tube in the ear they are usually uncomfortable.
Accordingly it would be desirable to address the above-described problems with a BTE hearing aid which avoids the occlusion effect, can be used without an expensive custom made ear mold, and provides an aesthetically pleasing and comfortable device.